What are the categories of ancient poetry?

Ancient poems before Tang Dynasty.

After the Tang Dynasty, it can be divided into ancient poetry (ancient style) and modern poetry (modern poetry, metrical poetry).

Antique can be divided into: general antique (including five-character ancient poems and seven-character ancient poems) and antique quatrains.

Modern poetry includes: regular poems (five-character regular poems, seven-character regular poems and "long-character regular poems") and quatrains (five-character quatrains and seven-character quatrains).

That's it in a nutshell. Please refer to the reference book for details.